The West Indian manatee is a large, plant-eating aquatic mammal that congregates for much of the year in shallow coastal areas and warm water canals. Unfortunately, these are also the locations traversed by many recreational and commercial vessels. As a result, the manatee is being injured and killed by collisions with vessel hulls and propellers.
In an effort to reduce such collisions, a variety of solutions have been proposed and/or tried. The solutions include regulating vessel speeds in areas frequented by manatees, performing aerial surveillance during specified times (e.g., boat races, times of high boat traffic, during times of high performance boat/motor testing, etc.,), instituting a moratoria on permits for marinas and other facilitates in areas frequented by manatees, and various forms of manatee detection schemes such as use of volunteer “spotters”, signals between boaters and acoustic detection. Obviously, a robust mechanized method of manatee detection is the preferred approach. However, the high noise environment of shallow coastal waters has, thus far, led to acoustic detection schemes having high false alarm rates. Detection schemes with high false alarm rates lead to unnecessary boat maneuvering and, over time, a loss of user confidence in the detection scheme.